Cogeneration system

ABSTRACT

A cogeneration system includes a compression air conditioner including a compressor, a first heat exchanger and a second heat exchanger; an absorption air conditioner including a regenerator, an absorber, a third heat exchanger and a fourth heat exchanger; a generator which generates electricity; a drive source which drives the generator to generate the electricity for operating the compression air conditioner and the absorption air conditioner and generates waste heat when driving the generator; and a waste heat recoverer which recovers the waste heat of the drive source and supplies the recovered waste heat to at least one of the compression air conditioner and the absorption air conditioner.

This Nonprovisional Application claims priority under 35 U.S.C. §119(a) on Patent Application No. 10-2004-0104362 filed in Korea on Dec. 10, 2004, the entire contents of which are hereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a cogeneration system, and, more particularly, to a cogeneration system in which waste heat of a drive source such as an engine is used in at least one of a compression type air conditioner and an absorption type air conditioner, thereby being capable of achieving an enhancement in system efficiency.

2. Description of the Related Art

In general, cogeneration systems are adapted to generate both electricity and heat from a single energy source.

Such a cogeneration system can recover the heat of the exhaust gas or waste heat of cooling water generated from an engine or turbine during an electricity generation operation, so that the cogeneration system can achieve an increase in energy efficiency of 70 to 80% over other systems. By virtue of such an advantage, the cogeneration system has recently been highlighted as an electricity and heat supply source for buildings. In particular, the cogeneration system exhibits highly-efficient energy utilization in that the recovered waste heat is mainly used to heat/cool a confined space and to heat water.

In general, such a cogeneration system include an engine, a generator to generate electricity, using a rotating force outputted from the engine, a heat pump type air conditioner, which is operated with the electricity generated from the generator, and is switched between cooling and heating modes, a thermal storage tank to heat water for supply of hot water, and a heat supply line to supply the heat of the exhaust gas discharged from the engine and heat of cooling water used to cool the engine.

The heat pump type air conditioner includes a compressor, a reversing valve, an indoor heat exchanger, an expansion device, and an outdoor heat exchanger, which are connected in series by a refrigerant conduit.

Hereinafter, operation of a conventional cogeneration system, which has the above-mentioned configuration, will be described.

When the engine drives, a rotor of the generator is rotated by an output shaft of the engine, so that the generator generates electricity. The generated electricity is used to operate various electronic appliances such as the heat pump type air conditioner and home illumination devices.

Meanwhile, the waste heat generated from the engine is supplied to the thermal storage tank via the heat supply line so that the supplied waste heat is used as a heat source to heat water.

When the heat pump type air conditioner operates in a heating mode, the compressor is driven to compress a refrigerant. At this time, the reversing valve establishes a flow path to allow the compressed refrigerant to circulate through the indoor heat exchanger, expansion device, outdoor heat exchanger, and compressor, in the order named. The indoor heat exchanger functions as a condenser to heat indoor air.

On the other hand, when the heat pump type air conditioner operates in a cooling mode, the compressor is driven to compress a refrigerant. At this time, the reversing valve establishes a flow path to allow the compressed refrigerant to circulate through the outdoor heat exchanger, expansion device, indoor heat exchanger, and compressor, in the order named. The indoor heat exchanger functions as an evaporator to cool indoor air.

However, the above-mentioned conventional cogeneration system is inefficient because the waste heat of the engine is used only to heat water for supplying hot water.

SUMMARY OF THE INVENTION

The present invention has been made in view of the above-mentioned problems. It is an object of the invention to provide a cogeneration system in which the waste heat of an engine of the cogeneration system is used during both heating and cooling operations of a heat pump type air conditioner of the cogeneration system, and thus, to enhance the system efficiency.

In accordance with one aspect of the present invention, a cogeneration system according to an embodiment comprises: a generator; a drive source operating to drive the generator, thereby causing the generator to generate electricity, the drive source generating waste heat during the operation of the drive source; a compression type air conditioner comprising a compressor, a reversing valve, an indoor heat exchanger, an expansion device, and an outdoor heat exchanger; an absorption type air conditioner comprising a regenerator, an absorber, a reversing valve, an indoor heat exchanger, an expansion device, and an outdoor heat exchanger; and a waste heat recoverer adapted to recover the waste heat of the drive source, and to supply the recovered waste heat to at least one of the compression type air conditioner and the absorption type air conditioner.

The waste heat recoverer according to an embodiment may comprise an exhaust gas heat exchanger adapted to absorb heat from exhaust gas discharged from the drive source, a cooling water heat exchanger adapted to absorb heat from cooling water used to cool the drive source, and a heat transfer unit to transfer the heat from at least one of the exhaust gas heat exchanger and the cooling water heat exchanger to the compression type air conditioner or to the absorption type air conditioner.

The heat transfer unit according to an embodiment may comprise a heat medium circulation conduit adapted to guide a heat medium, which has been heated by at least one of the exhaust gas heat exchanger and the cooling water heat exchanger, into the regenerator, thereby causing the heat medium to transfer the heat to the regenerator, and a heat medium circulation pump adapted to pump the heat medium for circulation of the heat medium.

The cogeneration system according to an embodiment may further comprise a cooling heat exchanger adapted to cool the heat medium, which has been heated by at least one of the exhaust gas heat exchanger and the cooling water heat exchanger, when the absorption type air conditioner is in an OFF state, and a cooling heat exchanger circulation conduit connected to the heat medium circulation conduit to guide the heat medium to circulate through the cooling heat exchanger.

The cogeneration system according to an embodiment may further comprise a valve unit adapted to control the heat medium circulation conduit and the cooling heat exchanger circulation conduit such that the heat medium circulates through the cooling heat exchanger circulation conduit when the absorption type air conditioner is in the OFF state, and circulates through the heat medium circulation conduit when the absorption type air conditioner is in an ON state.

The heat medium circulation conduit according to an embodiment may guide the heat medium, which has been heated by the cooling water heat exchanger, such that the heat medium is re-heated in the exhaust gas heat exchanger, and then returns to the cooling water heat exchanger after transferring the heat to the regenerator.

In accordance with another aspect of the present invention, a cogeneration system according to another embodiment comprises: a generator; a drive source operating to drive the generator, thereby causing the generator to generate electricity, the drive source generating waste heat during the operation of the drive source; a compression type air conditioner comprising a compressor, a reversing valve, an indoor heat exchanger, an expansion device, and an outdoor heat exchanger; an absorption type air conditioner comprising a regenerator, an absorber, a reversing valve, an indoor heat exchanger, an expansion device, and an outdoor heat exchanger; a waste heat recoverer adapted to recover the waste heat of the drive source, and to supply the recovered waste heat to at least one of the compression type air conditioner and the absorption type air conditioner; and a suction-side overheating heat exchanger adapted to supply the waste heat recovered by the waste heat recoverer to the compression type air conditioner.

The waste heat recoverer according to an embodiment may comprise an exhaust gas heat exchanger adapted to absorb heat from exhaust gas discharged from the drive source, a cooling water heat exchanger adapted to absorb heat from cooling water used to cool the drive source, and a heat transfer unit to transfer the heat from at least one of the exhaust gas heat exchanger and the cooling water heat exchanger to the compression type air conditioner or to the absorption type air conditioner.

The heat transfer unit according to an embodiment may comprise a first heat medium circulation conduit adapted to guide a heat medium, which has been heated by one of the exhaust gas heat exchanger and the cooling water heat exchanger, into the regenerator, thereby causing the heat medium to transfer the heat to the regenerator, and a second heat medium circulation conduit adapted to guide a heat medium, which has been heated by the other one of the exhaust gas heat exchanger and the cooling water heat exchanger, into the suction-side overheating heat exchanger, thereby causing the heat medium to transfer the heat to the suction-side overheating heat exchanger.

The first heat medium circulation conduit according to an embodiment may guide the heat medium, which has been heated by the exhaust gas heat exchanger, such that the heat medium returns to the exhaust gas heat exchanger after transferring the heat to the regenerator. The second heat medium circulation conduit according to an embodiment may guide the heat medium, which has been heated by the cooling water heat exchanger, such that the heat medium returns to the cooling water heat exchanger after transferring the heat to the suction-side overheating heat exchanger.

The cogeneration system according to an embodiment may further comprise a cooling heat exchanger adapted to cool the heat medium, which has been heated by at least one of the exhaust gas heat exchanger and the cooling water heat exchanger, when the absorption type air conditioner is in an OFF state or when the compression type air conditioner operates in a cooling mode, a first cooling heat exchanger circulation conduit connected between the cooling heat exchanger and the first heat medium circulation conduit, and a second cooling heat exchanger circulation conduit connected between the cooling heat exchanger and the second heat medium circulation conduit.

The cogeneration system according to an embodiment may further comprise a first valve unit adapted to guide the heat medium such that the heat medium circulates through the second cooling heat exchanger circulation conduit during the cooling mode of the compression type air conditioner, and circulates through the second heat medium circulation conduit during the heating mode of the compression type air conditioner.

The cogeneration system according to an embodiment may further comprise a refrigerant circulation conduit adapted to guide a refrigerant to be sucked into the compressor, a bypass conduit adapted to bypass the refrigerant, which is sucked toward the compressor, through the suction-side overheating heat exchanger during the heating mode of the compression type air conditioner, and a second valve unit adapted to guide the refrigerant, which is sucked toward the compressor, to pass through a selected one of the refrigerant circulation conduit and the bypass conduit.

The heat transfer unit according to an embodiment may comprise a first heat medium circulation conduit adapted to guide the heat medium, which has been heated by the cooling water heat exchanger, such that the heat medium is re-heated by the exhaust gas heat exchanger, and then returns to the cooling water heat exchanger after transferring the heat to the regenerator, and a second heat medium circulation conduit connected to the first heat medium circulation conduit to guide the heat medium, which emerges from the regenerator, to be bypassed through the suction-side overheating heat exchanger during the heating mode of the compression type air conditioner.

The cogeneration system according to an embodiment may further comprise a first valve unit adapted to control the first heat medium circulation conduit and the second heat medium circulation conduit such that the heat medium circulates through the first heat medium circulation conduit when the absorption type air conditioner is in an ON state, and the compression type air conditioner operates in a cooling mode, and the heat medium, which emerges from the regenerator, circulates through the suction-side overheating heat exchanger via the second heat medium circulation conduit during the heating mode of the compression type air conditioner.

The cogeneration system according to an embodiment may further comprise a third heat medium circulation conduit connected to the first heat medium circulation conduit to guide the heat medium such that the heat medium bypasses the regenerator 11 when the absorption type air conditioner is in an OFF state.

The cogeneration system according to an embodiment may further comprise a second valve unit adapted to control the first heat medium circulation conduit and the third heat medium circulation conduit such that the heat medium passes through the third heat medium circulation conduit when the absorption type air conditioner is in the OFF state, and passes through the first heat medium circulation conduit when the absorption type air conditioner is in the ON state.

The cogeneration system according to an embodiment may further comprise a cooling heat exchanger adapted to cool the heat medium during the cooling mode of the compression type air conditioner, and a cooling heat exchanger circulation conduit connected to the second heat medium circulation conduit to guide the heat medium to circulate through the cooling heat exchanger.

The cogeneration system according to an embodiment may further comprise a third valve unit adapted to control the second heat medium circulation conduit and the cooling heat exchanger circulation conduit such that the heat medium circulates through the cooling heat exchanger circulation conduit during the cooling mode of the compression type air conditioner in the OFF state of the absorption type air conditioner, and circulates through the second heat medium circulation conduit during the heating mode of the compression type air conditioner.

The cogeneration system according to an embodiment may further comprise a refrigerant circulation conduit adapted to guide a refrigerant to be sucked into the compressor, a bypass conduit adapted to bypass the refrigerant, which is sucked toward the compressor, through the suction-side overheating heat exchanger during the heating mode of the compression type air conditioner, and a fourth valve unit adapted to guide the refrigerant, which is sucked toward the compressor, to pass through a selected one of the refrigerant circulation conduit and the bypass conduit.

In accordance with another aspect of the present invention, a method of utilizing waste heat of a drive source according to an embodiment, comprise the steps of generating the waste heat from the drive source when the drive source drives to generate electricity; and supplying the waste heat to at least one of a compression air conditioner and a absorption air conditioner.

Further scope of applicability of the present application will become more apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus are not limitative of the present invention and wherein:

FIG. 1 is a schematic diagram of a cogeneration system according to a first embodiment of the present invention, illustrating the condition in which an absorption type air conditioner of the cogeneration system is in an ON state;

FIG. 2 is a schematic diagram of the cogeneration system according to the first embodiment of the present invention, illustrating the condition of the absorption type air conditioner is in an OFF state;

FIG. 3 is a schematic diagram of a cogeneration system according to a second embodiment of the present invention, illustrating the condition in which both an absorption type air conditioner and a compression type air conditioner of the cogeneration system operate in a heating mode;

FIG. 4 is a schematic diagram of the cogeneration system according to the second embodiment of the present invention, illustrating the condition in which the absorption type air conditioner is in an OFF state, and the compression type air conditioner operates in a heating mode;

FIG. 5 is a schematic diagram of the cogeneration system according to the second embodiment of the present invention, illustrating the condition in which the absorption type air conditioner operates in a heating mode, and the compression type air conditioner is in an OFF state;

FIG. 6 is a schematic diagram of the cogeneration system according to the second embodiment of the present invention, illustrating the condition in which both the absorption type air conditioner and the compression type air conditioner are in a cooling mode;

FIG. 7 is a schematic diagram of a cogeneration system according to a third embodiment of the present invention, illustrating the condition in which both an absorption type air conditioner and a compression type air conditioner of the cogeneration system operate in a heating mode;

FIG. 8 is a schematic diagram of the cogeneration system according to the third embodiment of the present invention, illustrating the condition in which the absorption type air conditioner is in an OFF state, and the compression type air conditioner operates in a heating mode;

FIG. 9 is a schematic diagram of the cogeneration system according to the third embodiment of the present invention, illustrating the condition in which the absorption type air conditioner operates in a heating mode, and the compression type air conditioner is in an OFF state;

FIG. 10 is a schematic diagram of the cogeneration system according to the third embodiment of the present invention, illustrating the condition in which both the absorption type air conditioner and the compression type air conditioner are in a cooling mode; and

FIG. 11 is a schematic diagram of the cogeneration system according to the third embodiment of the present invention, illustrating the condition in which the absorption type air conditioner is in an OFF state, and the compression type air conditioner operates in a cooling mode.

DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

Hereinafter, exemplary embodiments of a cogeneration system according to the present invention will be described with reference to the annexed drawings. In the following description, identical elements are referred to by the same title and designated by the same reference numeral, without any redundant description thereof.

FIG. 1 is a schematic diagram of a cogeneration system according to a first embodiment of the present invention, illustrating the condition in which an absorption type air conditioner of the cogeneration system is in an ON state. FIG. 2 is a schematic diagram of the cogeneration system according to the first embodiment of the present invention, illustrating the condition in which the absorption type air conditioner is in an OFF state.

As shown in FIGS. 1 and 2, the cogeneration system according to the first embodiment of the present invention includes a generator 2, and a drive source. The drive source operates to drive the generator 2 for generating electricity, and generates waste heat during operation thereof. The cogeneration system also includes a compression type air conditioner 10 and an absorption type air conditioner 20. The compression type air conditioner 10 includes a compressor 3, a first reversing valve 4, a first indoor heat exchanger 5, a first expansion device 6, and a first outdoor heat exchanger 7. The absorption type air conditioner 20 includes a regenerator 11, an absorber 12, a second reversing valve 13, a second indoor heat exchanger 14, a second expansion device 15, and a second outdoor heat exchanger 16. The cogeneration system further includes a waste heat recoverer adapted to recover the waste heat of the drive source, and to supply the recovered waste heat to at least one of the compression type air conditioner 10 and absorption type air conditioner 20.

The generator 2 may be an AC generator or a DC generator. The generator 2 includes a rotor coupled to an output shaft of the drive source so that the generator 2 generates electricity during rotation of the output shaft. The drive source comprises an engine 8, a fuel cell, or the like. The following description will be given only in conjunction with an embodiment in which the drive source comprises the engine 8.

The engine 8 includes a combustion chamber defined in the interior of the engine 8. A fuel tube 8 a and an exhaust tube 8 b are connected to the engine 8. The fuel tube 8 a is adapted to supply fuel such as liquefied gas or liquefied petroleum gas into the combustion chamber. The exhaust tube 8 b is adapted to guide the exhaust gas discharged from the combustion chamber.

The compression type air conditioner 10 is of a heat pump type in the illustrated embodiment. The compression type air conditioner 10 is connected with the generator 2 via a power line, so as to use the electricity generated from the generator 2 for driving of the compressor 3.

A first indoor fan 5 a is arranged near the first indoor heat exchanger 5 to force the indoor air to pass around the first indoor heat exchanger 5. The first indoor heat exchanger 5 and the first indoor fan 5 a constitute an indoor unit of the compression type air conditioner 10.

A first outdoor fan 7 a is arranged near the first outdoor heat exchanger 7 to force the outdoor air to pass around the first outdoor heat exchanger 7. The outdoor fan 7 a constitutes an outdoor unit of the compression type air conditioner 10, together with the compressor 3, the first reversing valve 4, the first expansion device 6, and the first outdoor heat exchanger 7.

Similar to the compression type air conditioner 10, the absorption type air conditioner 20 is of a heat pump type in the illustrated embodiment. The regenerator 11 of the absorption type air conditioner 20 produces refrigerant vapor (e.g., pure ammonia vapor) and a dilute solution (e.g., an aqueous ammonia solution with a low ammonia concentration) from a concentrated solution (e.g., an aqueous ammonia solution with a high ammonia concentration), using heat received from the waste heat recoverer. In addition to the regenerator 11, the absorption type air conditioner 20 includes a condenser adapted to heat-exchange with outdoor air to condense the refrigerant vapor produced by the regenerator 11. The second outdoor heat exchanger 16 functions as the condenser during the cooling mode of the absorption type air conditioner 20. The second indoor heat exchanger 14 functions as the condenser during the heating mode of the absorption type air conditioner 20. The absorption type air conditioner 20 also includes an evaporator adapted to heat-exchange with outdoor air to change refrigerant liquid into refrigerant vapor. The second indoor heat exchanger 14 functions as the evaporator during the cooling mode of the absorption type air conditioner 20. The second outdoor heat exchanger 16 functions as the evaporator during the heating mode of the absorption type air conditioner 20. The absorber 12 of the absorption type air conditioner 20 causes the dilute solution produced by the regenerator 11 to absorb the refrigerant vapor discharged from the evaporator, thereby producing a concentrated solution. The absorption type air conditioner 20 further includes a solution heat exchanger 17 adapted to cause the refrigerant vapor produced by the regenerator 11 to heat-exchange with the concentrated solution discharged from the absorber 12, thereby increasing the concentration of the refrigerant vapor.

A second indoor fan 14 a is arranged near the second indoor heat exchanger 14 to force the indoor air to pass around the second indoor heat exchanger 14. A second outdoor fan 16 a is arranged near the second outdoor heat exchanger 16 to force the outdoor air to pass around the second outdoor heat exchanger 14.

The second reversing valve 13, which is also included in the absorption type air conditioner 20, changes the refrigerant flow path when the absorption type air conditioner 20 is switched between cooling and heating modes.

A solution pump 18 and an expansion valve 19 are arranged between the absorber 12 and the solution heat exchanger 17. The solution pump 18 pumps the concentrated solution from the absorber 12 to the solution heat exchanger 17. The expansion valve 19 reduces the pressure of the dilute solution cooled in accordance with the heat exchange thereof in the solution heat exchanger 17, and guides the dilute solution to the absorber 12.

Meanwhile, the waste heat recoverer includes an exhaust gas heat exchanger 21 adapted to absorb heat from the exhaust gas discharged from the engine 8, and a cooling water heat exchanger 22 adapted to absorb heat from the cooling water used to cool the engine 8. The waste heat recoverer also includes a heat transfer unit adapted to transfer the heat from at least one of the exhaust gas heat exchanger 21 and the cooling water heat exchanger 22 to the compression type air conditioner 10 or absorption type air conditioner 20.

In the following description, it is assumed that, in the first embodiment, the heat recovered by the waste heat recoverer is transferred only to the absorption type air conditioner 20, and the compression type air conditioner 10 receives only the electricity generated from the generator 2.

The exhaust gas heat exchanger 21 is connected to the engine 8 via the exhaust tube 8 b. An exhaust tube 23 is connected to the exhaust gas heat exchanger 21 to guide the exhaust gas passing through the exhaust gas heat exchanger 21 to be discharged to the atmosphere.

The cooling water heat exchanger 22 is connected with the engine 8 via a cooling water circulation conduit 24. Accordingly, cooling water, which is heated while cooling the engine 8, is fed to the cooling water heat exchanger 22 via the cooling water circulation conduit 24, and then returns to the engine 8 via the cooling water circulation conduit 24 after transferring the heat to the cooling water heat exchanger 22. For the circulation of the cooling water, a cooling water circulation pump 25 is arranged at the cooling water circulation conduit 24.

The heat transfer unit includes a heat medium circulation conduit 26 adapted to guide a heat medium, which has been heated by at least one of the exhaust gas heat exchanger 21 and the cooling water heat exchanger 22, to the regenerator 11, so as to allow the heat medium to transfer the heat to the regenerator 11. The heat transfer unit also includes a heat medium circulation pump 27 adapted to pump the heat medium for circulation of the heat medium.

The following description will be given only in conjunction with the embodiment in which the heat medium circulation conduit 26 guides the heat medium, which has been heated while sequentially passing through the cooling water heat exchanger 22 and exhaust gas heat exchanger 21, to the regenerator 11, and then to return to the cooling water heat exchanger 22 after transferring the heat to the regenerator 11.

Meanwhile, the cogeneration system further includes a cooling heat exchanger 28 adapted to cool the heat medium in an OFF state of the absorption type air conditioner 20. A cooling heat exchanger circulation conduit 29 is connected between the cooling heat exchanger 28 and the heat medium circulation conduit 26, in order to allow the heat medium to circulate through the cooling heat exchanger 28.

The cogeneration system further includes a valve unit adapted to guide the heat medium to circulate through the cooling heat exchanger circulation conduit 29 in the OFF state of the absorption type air conditioner 20, and to circulate through the heat medium circulation conduit 26 in the ON state of the absorption type air conditioner 20.

The valve unit includes a first 3-way valve 30 arranged at a portion of the heat medium circulation conduit 26, to which one end of the cooling heat exchanger circulation conduit 29 is connected, in order to guide the heat medium, which has been heated while sequentially passing through the cooling water heat exchanger 22 and exhaust gas heat exchanger 21, to the cooling heat exchanger 28. The valve unit also includes a second 3-way valve 31 arranged at a portion of the heat medium circulation conduit 26, to which the other end of the cooling heat exchanger circulation conduit 29 is connected, in order to guide the heat medium, which has been cooled while passing through the cooling heat exchanger 28, to the cooling water heat exchanger 22.

The cogeneration system further includes a controller (not shown) for not only controlling the compression type air conditioner 10 and absorption type air conditioner 20, but also performing control operations to supply the electricity from the generator 2 only to the compression type air conditioner 10 when only the compression type air conditioner 10 operates, and only to the absorption type air conditioner 20 when only the absorption type air conditioner 20 operates.

Hereinafter, operation of the cogeneration system according to the first embodiment of the present invention will be described.

When fuel is supplied to the engine 8 via the fuel tube 8 a, the engine 8 is driven, so that the output shaft of the engine 8 is rotated, thereby causing the generator 2 to generate electricity.

Exhaust gas, which is discharged from the engine 8 during the operation of the engine 8, releases heat to the exhaust gas heat exchanger 21 while passing through the exhaust gas heat exchanger 21, and is then discharged to the atmosphere.

During the operation of the engine 8, the cooling water pump 25 is driven, so that the cooling water, which is heated while cooling the engine 8, is fed to the cooling water heat exchanger 22 via the cooling water circulation conduit 24. After releasing heat to the cooling water heat exchanger 22, the cooling water returns to the engine 8 via the cooling water circulation conduit 24.

The electricity generated from the generator 2 is used to drive the compressor 3 of the compression type air conditioner 10. The electricity generated from the generator 2 is also supplied to the regenerator 11 of the absorption type air conditioner 20.

Meanwhile, when the absorption type air conditioner 20 is switched on to operate in a heating mode, the second reversing valve 13 is switched to a heating mode, as shown in FIG. 1. Also, the first and second 3-way valves 30 and 31 are controlled to operate in an ON mode, and the heat medium circulation pump 27 is driven.

That is, the first and second 3-way valves 30 and 31 close the cooling heat exchanger circulation conduit 29, while opening the heat medium circulation conduit 26. The heat medium circulation pump 27 pumps the heat medium.

The heat medium pumped by the heat medium circulation pump 27 is heated while passing through the cooling water heat exchanger 22, and is then introduced into the exhaust gas heat exchanger 21. The heat medium is again heated by the exhaust gas heat exchanger 21, and is then introduced into the regenerator 11 through the heat medium circulation conduit 26. Accordingly, the heat medium transfers heat to the regenerator 11.

Using the transferred heat, the regenerator 11 produces refrigerant vapor from a concentrated solution contained in the regenerator 11. At this time, a dilute solution is also produced which is a portion of the concentrated solution remaining without being changed into the refrigerant vapor.

The refrigerant produced in the regenerator 11 is supplied to the solution heat exchanger 17. The refrigerant is rectified in the solution heat exchanger 17 while heat-exchanging with a concentrated solution supplied from the absorber 12 to the solution heat exchanger 17. The rectified refrigerant is introduced into the absorber 12 after passing through the second reversing valve 13, second indoor heat exchanger 14, second expansion device 15, second outdoor heat exchanger 16, and second reversing valve 13, in the order named. In this case, the second indoor heat exchanger 14 functions as a condenser to heat indoor air.

On the other hand, when the absorption type air conditioner 20 is switched to operate in a cooling mode, the second reversing valve 13 is switched to a cooling mode. In this case, the flow path of the refrigerant is changed from that of a heating mode, but the flow path of the heat medium is not changed from that of a heating mode. That is, the principle of producing refrigerant vapor in the regenerator 11 using heat transferred from the heat medium to the regenerator 11 in a cooling mode is identical to that of a heating mode.

In other words, since the regenerator 11 is configured to produce refrigerant vapor using a heat source, the regenerator 11 always requires heat of the heat medium regardless of the operating mode (that is, cooling or heating mode) of the absorption type air conditioner 20 as long as the absorption air conditioner 20 is in operation.

On the other hand, when the absorption type air conditioner 20 is switched off, the first and second 3-way valves 30 and 31 are controlled to operate in an OFF mode, thereby opening the cooling heat exchanger circulation conduit 29.

In this case, the heat medium pumped by the heat medium circulation pump 27 sequentially passes through the cooling water heat exchanger 22 and exhaust gas heat exchanger 21, and then enters the cooling heat exchanger 28 via the first 3-way valve 30.

The heat medium entering the cooling heat exchanger 28 releases heat in the cooling heat exchanger 28, and returns the cooling water heat exchanger 22 after passing through the heat medium circulation conduit 26 via the second 3-way valve 31.

FIG. 3 is a schematic diagram of a cogeneration system according to a second embodiment of the present invention, illustrating the condition in which both an absorption type air conditioner and a compression type air conditioner of the cogeneration system operate in a heating mode. FIG. 4 is a schematic diagram of the cogeneration system according to the second embodiment of the present invention, illustrating the condition in which the absorption type air conditioner is in an OFF state, and the compression type air conditioner operates in a heating mode. FIG. 5 is a schematic diagram of the cogeneration system according to the second embodiment of the present invention, illustrating the condition in which the absorption type air conditioner operates in a heating mode, and the compression type air conditioner is in an OFF state. FIG. 6 is a schematic diagram of the cogeneration system according to the second embodiment of the present invention, illustrating the condition in which both the absorption type air conditioner and the compression type air conditioner are in a cooling mode. In FIGS. 3 to 6, reference numerals respectively corresponding to those in FIGS. 1 and 2 are designated as the same reference numerals.

As shown in FIGS. 3 to 6, the cogeneration system according to the second embodiment of the present invention includes a generator 2, and a drive source which operates to drive the generator 2 for generating electricity, and generates waste heat during operation thereof. The cogeneration system also includes a compression type air conditioner 10 and an absorption type air conditioner 20. The compression type air conditioner 10 includes a compressor 3, a first reversing valve 4, a first indoor heat exchanger 5, a first expansion device 6, and a first outdoor heat exchanger 7. The an absorption type air conditioner 20 includes a regenerator 11, an absorber 12, a second reversing valve 13, a second indoor heat exchanger 14, a second expansion device 15, and a second outdoor heat exchanger 16. The cogeneration system further includes a waste heat recoverer adapted to recover the waste heat of the drive source and to supply the recovered waste heat to at least one of the compression type air conditioner 10 and absorption type air conditioner 20, and a suction-side overheating heat exchanger 44 adapted to heat a refrigerant sucked into the compressor 3 during the heating mode of the compression type air conditioner 10.

The waste heat recoverer includes an exhaust gas heat exchanger 21 adapted to absorb the heat from the exhaust gas discharged from the drive source (hereinafter, referred to as an engine 8), and a cooling water heat exchanger 22 adapted to absorb the heat from the cooling water used to cool the engine 8. The waste heat recoverer also includes a heat transfer unit adapted to transfer the heat from at least one of the exhaust gas heat exchanger 21 and the cooling water heat exchanger 22 to the compression type air conditioner 10 or the absorption type air conditioner 20.

The heat transfer unit includes a first heat medium circulation conduit 40 adapted to guide a heat medium, which has been heated by at least one of the exhaust gas heat exchanger 21 and the cooling water heat exchanger 22, to the regenerator 11, so as to allow the heat medium to transfer the heat to the regenerator 11. The heat transfer unit also includes a second heat medium circulation conduit 45 adapted to guide the heat medium heated by at least one of the exhaust gas heat exchanger 21 and the cooling water heat exchanger 22, to the suction-side overheating heat exchanger 44, so as to allow the heat medium to transfer the heat to the suction-side overheating heat exchanger 44.

The heat transfer unit further includes a first heat medium circulation pump 41 arranged at the first heat medium circulation conduit 40 to pump the heat medium, which passes through the first heat medium circulation conduit 40, and a second heat medium circulation pump 46 arranged at the second heat medium circulation conduit 45 to pump the heat medium, which passes through the second heat medium circulation conduit 45.

The cogeneration system of the second embodiment has the same configuration and functions as those of the first embodiment in terms of the generator 2, drive source, compression type air conditioner 10, absorption type air conditioner 20, exhaust gas heat exchanger 21, and the cooling water heat exchanger 22, except that the first heat medium circulation conduit 40 guides circulation of only the heat medium heated by the exhaust gas heat exchanger 21. Accordingly, the constituent elements of the second embodiment respectively corresponding to those of the first embodiment are designated as the same reference numerals, and no detailed description thereof will be given.

Meanwhile, the cogeneration system further includes a cooling heat exchanger 42 adapted to cool the heat medium heated by the exhaust gas heat exchanger 21 in the OFF state of the absorption type air conditioner 20. A first cooling heat exchanger circulation conduit 43 is connected between the cooling heat exchanger 42 and the first heat medium circulation conduit 40, in order to allow the heat medium heated by the exhaust gas heat exchanger 21 to circulate through the cooling heat exchanger 42.

The cogeneration system further includes a first valve unit adapted to control open/close of the first cooling heat exchanger circulation conduit 43 and the first heat medium circulation conduit 41 such that the heat medium circulates through the first cooling heat exchanger circulation conduit 43 in the OFF state of the absorption type air conditioner 20, and circulates through the first heat medium circulation conduit 40 in the ON state of the absorption type air conditioner 20.

The first valve unit includes a first 3-way valve 51 arranged at a portion of the first heat medium circulation conduit 41, to which one end of the cooling heat exchanger circulation conduit 43 is connected, and a second 3-way valve 52 arranged at a portion of the first heat medium circulation conduit 41, to which the other end of the cooling heat exchanger circulation conduit 43 is connected.

The following description will be given only in conjunction with the case in which the first heat medium circulation conduit 40 guides only the heat medium heated by the exhaust gas heat exchanger 21 to return to the exhaust gas heat exchanger 21 after transferring the heat to the regenerator 11, and the second heat medium circulation conduit 45 guides only the heat medium heated by the cooling water heat exchanger 22 to return to the cooling water heat exchanger 22 after transferring the heat to the suction-side overheating heat exchanger 44.

A second cooling heat exchanger circulation conduit 47 is connected between the cooling heat exchanger 42 and the second heat medium circulation conduit 45, in order to allow the heat medium heated by the cooling water heat exchanger 22 during the cooling mode of the compression type air conditioner 10 to circulate through the cooling heat exchanger 42.

The cogeneration system further includes a second valve unit adapted to guide the heat medium to circulate through the second cooling heat exchanger circulation conduit 47 during the cooling mode of the compression type air conditioner 10, and to circulate through the second heat medium circulation conduit 45 during the heating mode of the compression type air conditioner 10.

The second valve unit includes a third 3-way valve 53 arranged at a portion of the second heat medium circulation conduit 45, to which one end of the second cooling heat exchanger circulation conduit 47 is connected, in order to guide the heat medium, which has been heated while passing through the cooling water heat exchanger 22, to circulate through the second cooling heat exchanger circulation conduit 47. The second valve unit also includes a fourth 3-way valve 54 arranged at a portion of the second heat medium circulation conduit 45, to which the other end of the second cooling heat exchanger circulation conduit 47 is connected, in order to guide the heat medium, which has been cooled while passing through the cooling heat exchanger 42, to circulate through the cooling water heat exchanger 22.

The cogeneration system further includes a refrigerant circulation conduit 48 adapted to guide the refrigerant to be sucked into the compressor 3, a bypass conduit 49 adapted to bypass the refrigerant, which is sucked toward the compressor 3 during the heating mode of the compression type air conditioner 10, through the suction-side overheating heat exchanger 44, and a third valve unit adapted to allow the refrigerant sucked toward the compressor 3 to pass through a selected one of the refrigerant circulation conduit 48 and the bypass conduit 49.

The third valve unit includes a fifth 3-way valve 55 arranged at a portion of the refrigerant circulation conduit 48, to which an inlet of the bypass conduit 49 is connected, in order to guide the refrigerant into the bypass conduit 49, and a sixth 3-way valve 56 arranged at a portion of the refrigerant circulation conduit 48, to which an outlet of the bypass conduit 49 is connected, in order to guide the refrigerant emerging from the suction-side overheating heat exchanger 44 to circulate through the refrigerant circulation conduit 48.

0] The cogeneration system further includes a controller (not shown) for not only controlling the compression type air conditioner 10 and absorption type air conditioner 20, but also performing control operations to cause the second heat medium circulation pump 54 to be in an ON state during the heating mode of the compression type air conditioner 10, to cause the third and fourth 3-way valves 53 and 54 to operate in a heating mode during the heating mode of the compression type air conditioner 10, and to control the first and second 3-way valves 51 and 52 in accordance with the ON or OFF state of the absorption type air conditioner 20.

Hereinafter, operation of the cogeneration system according to the second embodiment of the present invention will be described.

First, when both the compression type air conditioner 10 and the absorption type air conditioner 20 operate in a heating mode, as shown in FIG. 3, electricity generated from the generator 2 is supplied to the regenerator 11 and compressor 3. The first and second reversing valves 4 and 13 operate in a heating mode, and the first, second, third, fourth, fifth, and sixth 3-way valves 51, 52, 53, 54, 55, and 56 operate in a heating mode. The first and second heat medium circulation pumps 41 and 46 are driven.

The first and second 3-way valves 51 and 52 close the first cooling heat exchanger circulation conduit 43 while opening the first heat medium circulation conduit 40, whereas the third and fourth 3-way valves 53 and 54 close the second cooling heat exchanger circulation conduit 47 while opening the second heat medium circulation conduit 45. The fifth and sixth 3-way valves 55 and 56 open the bypass conduit 49, thereby causing the refrigerant supplied toward the compressor 3 to be introduced into the suction-side overheating heat exchanger 44 via the bypass conduit 49.

The first and second heat medium circulation pumps 41 and 46 pump the heat medium.

The heat medium pumped by the first heat medium circulation pump 41 is heated while passing through the exhaust gas heat exchanger 21, and is then introduced into the regenerator 11 via the first heat medium circulation conduit 40. After transferring the heat to the regenerator 11, the heat medium returns to the exhaust gas heat exchanger 21.

The heat medium pumped by the second heat medium circulation pump 41 is heated while passing through the cooling water heat exchanger 22, and is then introduced into the suction-side overheating heat exchanger 44 via the second heat medium circulation conduit 45. After transferring the heat to the suction-side overheating heat exchanger 44, the heat medium returns to the cooling water heat exchanger 22.

The refrigerant introduced into the suction-side overheating heat exchanger 44 is heated by the heat medium introduced into the suction-side overheating heat exchanger 44 via the second heat medium circulation conduit 45. The heated refrigerant passes through the first reversing valve 4 and the first indoor heat exchanger 5 after being compressed by the compressor 3. Since the refrigerant is re-heated in the suction-side overheating heat exchanger 44, an increased amount of heat is released from the refrigerant. Accordingly, the heating performance of the compression type air conditioner 10 is enhanced.

On the other hand, when the compression type air conditioner 10 operates in a heating mode in the OFF state of the absorption type air conditioner 20, as shown in FIG. 4, the electricity generated from the generator 2 is supplied only to the compression type air conditioner 10. In this case, the first and second 3-way valves 51 and 52 are controlled to be in an OFF mode. On the other hand, the third, fourth, fifth, and sixth 3-way valves 53, 54, 55, and 56 are controlled to be in a heating mode.

Accordingly, the first and second 3-way valves 51 and 52 open the first cooling heat exchanger circulation conduit 43, thereby causing the heat medium heated by the exhaust gas heat exchanger 21 to be introduced into the cooling heat exchanger 22 via the first cooling heat exchanger circulation conduit 43 after passing through the first 3-way valve 51. Accordingly, the heat medium releases heat in the cooling heat exchanger 22.

The heat medium subsequently returns to the exhaust gas heat exchanger 21 via the second 3-way valve 52.

On the other hand, when the absorption type air conditioner 20 is in an ON state, and the compression type air conditioner 10 is in an OFF state, as shown in FIG. 5, the electricity generated from the generator 2 is supplied only to the absorption type air conditioner 20. In this case, the first and second 3-way valves 51 and 52 are controlled to be in an ON mode, whereas the third and fourth 3-way valves 53 and 54 are controlled to be in an OFF mode.

Accordingly, the first and second 3-way valves 51 and 52 open the first heat medium circulation conduit 40 while closing the first cooling heat exchanger circulation conduit 43, thereby causing the heat medium heated by the exhaust gas heat exchanger 21 to be introduced into the regenerator 11, and then to return to the exhaust gas heat exchanger 21.

On the other hand, the third and fourth 3-way valves 53 and 54 open the second cooling heat exchanger circulation conduit 47. Accordingly, the heat medium heated by the cooling water heat exchanger 22 is introduced into the cooling heat exchanger 42 via the second cooling heat exchanger circulation conduit 47. After releasing heat in the cooling heat exchanger 42, the heat medium returns to the cooling water heat exchanger 22 via the fourth 3-way valve 54.

When both the compression type air conditioner 10 and the absorption type air conditioner 20 operate in a cooling mode, as shown in FIG. 6, the first and second reversing valves 4 and 13 operate in a cooling mode. In this case, the first and second 3-way valves 51 and 52 are controlled to be in an ON mode, the second and fourth 3-way valves 53 and 54 are controlled to be in an OFF mode, and the fifth and sixth 3-way valves 55 and 56 are controlled to operate in a cooling mode.

In this case, since the absorption type air conditioner 20 requires a heat source supplied from the regenerator 11 regardless of the operation mode (cooling or heating mode) of the absorption type air conditioner 20, the heat medium emerging from the exhaust gas heat exchanger 21 is guided to be supplied to the regenerator 11, and the heat medium emerging from the cooling water heat exchanger 22 is prevented from being supplied to the suction-side overheating heat exchanger 44.

Accordingly, since the first heat medium circulation conduit 40 is opened by the first and second 3-way valves 51 and 52, the heat medium heated in the exhaust gas heat exchanger 21 is introduced into the regenerator 11 via the first heat medium circulation conduit 40, so that the heat medium transfers heat to the regenerator 11. As a result, refrigerant vapor is produced in the regenerator.

The refrigerant vapor produced in the regenerator 11 passes through the second reversing valve 13, second outdoor heat exchanger 16, second expansion device 15, and second indoor heat exchanger 14, in the order named, thereby cooling indoor air.

Meanwhile, since the second cooling heat exchanger circulation conduit 47 is opened by the third and fourth 3-way valves 53 and 54, the heat medium heated in the cooling water heat exchanger 22 is introduced into the cooling heat exchanger 42 via the second cooling heat exchanger circulation conduit 47. After releasing heat in the cooling heat exchanger 42, the heat medium returns to the cooling water heat exchanger 22.

Also, since the bypass conduit 49 is closed by the fifth and sixth 3-way valves 55 and 56, the refrigerant is directly sucked into the compressor 3 without passing through the suction-side overheating heat exchanger 44.

The refrigerant sucked into the compressor 3 passes through the first reversing valve 4, first outdoor heat exchanger 7, first expansion device 6, and the first indoor heat exchanger 5, in the order named, thereby cooling indoor air.

FIG. 7 is a schematic diagram of a cogeneration system according to a third embodiment of the present invention, illustrating the condition in which both an absorption type air conditioner and a compression type air conditioner of the cogeneration system operate in a heating mode. FIG. 8 is a schematic diagram of the cogeneration system according to the third embodiment of the present invention, illustrating the condition in which the absorption type air conditioner is in an OFF state, and the compression type air conditioner operates in a heating mode. FIG. 9 is a schematic diagram of the cogeneration system according to the third embodiment of the present invention, illustrating the condition in which the absorption type air conditioner operates in a heating mode, and the compression type air conditioner is in an OFF state. FIG. 10 is a schematic diagram of the cogeneration system according to the third embodiment of the present invention, illustrating the condition in which both the absorption type air conditioner and the compression type air conditioner are in a cooling mode. FIG. 11 is a schematic diagram of the cogeneration system according to the third embodiment of the present invention, illustrating the condition in which the absorption type air conditioner is in an OFF state, and the compression type air conditioner operates in a cooling mode. In FIGS. 7 to 11, reference numerals respectively corresponding to those in FIGS. 1 to 6 are designated as the same reference numerals.

As shown in FIGS. 7 to 11, the cogeneration system according to the third embodiment of the present invention includes a generator 2, and a drive source which operates to drive the generator 2 for generating electricity, and generates waste heat during operation thereof. The cogeneration system also includes a compression type air conditioner 10 and an absorption type air conditioner 20. The compression type air conditioner 10 includes a compressor 3, a first reversing valve 4, a first indoor heat exchanger 5, a first expansion device 6, and a first outdoor heat exchanger 7. The absorption type air conditioner 20 includes a regenerator 11, an absorber 12, a second reversing valve 13, a second indoor heat exchanger 14, a second expansion device 15, and a second outdoor heat exchanger 16. The cogeneration system further includes a waste heat recoverer adapted to recover the waste heat of the drive source and to supply the recovered waste heat to at least one of the compression type air conditioner 10 and absorption type air conditioner 20, and a suction-side overheating heat exchanger 62 adapted to heat a refrigerant sucked into the compressor 3 during the heating mode of the compression type air conditioner 10.

The waste heat recoverer includes an exhaust gas heat exchanger 21 adapted to absorb heat from the exhaust gas discharged from the drive source (hereinafter, referred to as an engine 8), and a cooling water heat exchanger 22 adapted to absorb heat from the cooling water used to cool the engine 8. The waste heat recoverer also includes a heat transfer unit adapted to transfer the heat from at least one of the exhaust gas heat exchanger 21 and the cooling water heat exchanger 22 to the compression type air conditioner 10 or absorption type air conditioner 20.

The heat transfer unit includes a first heat medium circulation conduit 60 adapted to guide a heat medium, which has been heated by at least one of the exhaust gas heat exchanger 21 and the cooling water heat exchanger 22, to the regenerator 11, so as to allow the heat medium to transfer the heat to the regenerator 11. The heat transfer unit also includes a second heat medium circulation conduit 63 connected to the first heat medium circulation conduit 60 to bypass the refrigerant, which emerges from the regenerator 11 during the heating mode of the compression type air conditioner 10, through the suction-side overheating heat exchanger 62.

The heat transfer unit further includes a heat medium circulation pump 61 arranged at the first heat medium circulation conduit 60 to pump the heat medium for circulation of the heat medium.

The cogeneration system of the third embodiment has the same configuration and functions as those of the first embodiment in terms of the generator 2, engine 8, compression type air conditioner 10, absorption type air conditioner 20, exhaust gas heat exchanger 21, and the cooling water heat exchanger 22, except that the first heat medium circulation conduit 60 guides the heat medium heated by the cooling water heat exchanger 22 into the exhaust gas heat exchanger 21 for re-heating of the heat medium, and then to return to the cooling water heat exchanger 22 after transferring the heat to the regenerator 11. Accordingly, the constituent elements of the second embodiment respectively corresponding to those of the first embodiment are designated as the same reference numerals, and no detailed description thereof will be given.

That is, the first heat medium circulation conduit 60 is connected to both the exhaust gas heat exchanger 21 and the cooling water heat exchanger 22.

The cogeneration system further includes a first valve unit adapted to control open/close of the first and second heat medium circulation conduits 60 and 63 such that the heat medium circulates through the first cooling heat exchanger circulation conduit 43 during the cooling mode of the compression type air conditioner 10, and the heat medium emerging from the regenerator 11 during the heating mode of the compression type air conditioner 10 circulates through the suction-side overheating heat exchanger 62 via the second heat medium circulation conduit 63.

The first valve unit includes a first 3-way valve 71 arranged at a portion of the first heat medium circulation conduit 60, to which one end of the second heat medium circulation conduit 63 is connected, and a second 3-way valve 72 arranged at a portion of the first heat medium circulation conduit 60, to which the other end of the second heat medium circulation conduit 63 is connected, in order to allow the heat medium emerging from the regenerator 11 to circulate through the second heat medium circulation conduit 63.

A third heat medium circulation conduit 64 is connected to the first heat medium circulation conduit 60, in order to guide the heat medium heated by the exhaust gas heat exchanger 21 to bypass the regenerator 11 when the absorption type air conditioner 20 is in an OFF state.

The cogeneration system further includes a second valve unit adapted to control open/close of the first and third heat medium circulation conduits 60 and 64 such that the heat medium passes through the third heat medium circulation conduit 64 when the absorption type air conditioner 20 is in an OFF state, and passes through the first heat medium circulation conduit 60 when the absorption type air conditioner 20 is in an ON state.

The second valve unit includes a third 3-way valve 73 arranged at a portion of the first heat medium circulation conduit 60, to which one end of the third heat medium circulation conduit 64 is connected, and a fourth 3-way valve 74 arranged at a portion of the first heat medium circulation conduit 60, to which the other end of the third heat medium circulation conduit 64 is connected, in order to guide the heat medium, which emerges from the exhaust gas heat exchanger 21 to pass through the third heat medium circulation conduit 64.

The cogeneration system further includes a cooling heat exchanger 65 adapted to cool the heat medium during the cooling mode of the compression type air conditioner 10, and a cooling heat exchanger circulation conduit 66 connected to the second heat medium circulation conduit 63 to guide the heat medium to circulate through the cooling heat exchanger 65.

The cogeneration system further includes a third valve unit adapted to open/close of the second heat medium circulation conduit 63 and cooling heat exchanger circulation conduit 66 such that the heat medium circulates through the cooling heat exchanger circulation conduit 66 during the cooling mode of the compression type air conditioner 10, and circulates through the second heat medium circulation conduit 63 during the heating mode of the compression type air conditioner 10.

The third valve unit includes a fifth 3-way valve 75 arranged at a portion of the second heat medium circulation conduit 63, to which one end of the cooling heat exchanger circulation conduit 66 is connected, and a sixth 3-way valve 76 arranged at a portion of the second heat medium circulation conduit 63, to which the other end of the cooling heat exchanger circulation conduit 66 is connected, in order to guide the heat medium into the cooling heat exchanger circulation conduit 66.

The cogeneration system further includes a refrigerant circulation conduit 67 adapted to guide the refrigerant to be sucked into the compressor 3 of the compression type air conditioner 10, a bypass conduit 68 adapted to bypass the refrigerant, sucked toward the compressor 3, through the suction-side overheating heat exchanger 62, and a fourth valve unit adapted to allow the refrigerant sucked toward the compressor 3 to pass through a selected one of the refrigerant circulation conduit 67 and bypass conduit 68.

The fourth valve unit includes a seventh 3-way valve 77 arranged at a portion of the refrigerant circulation conduit 67, to which an inlet of the bypass conduit 68 is connected, in order to guide the refrigerant into the bypass conduit 68, and an eighth 3-way valve 78 arranged at a portion of the refrigerant circulation conduit 67, to which an outlet of the bypass conduit 68 is connected, in order to guide the refrigerant emerging from the suction-side overheating heat exchanger 62 to circulate through the refrigerant circulation conduit 67.

The cogeneration system further includes a controller (not shown) for not only controlling the compression type air conditioner 10 and absorption type air conditioner 20, but also performing control operations to cause the heat medium circulation pump 61 to be in an ON state during the heating mode of the compression type air conditioner 10, to cause the third and fourth 3-way valves 73 and 74 to operate in a heating mode during the heating mode of the compression type air conditioner 10, and to control the first and second 3-way valves 71 and 72 in accordance with the ON or OFF state of the absorption type air conditioner 20.

Hereinafter, the operation of the cogeneration system according to the third embodiment of the present invention will be described.

First, when both the compression type air conditioner 10 and the absorption type air conditioner 20 operate in a heating mode, as shown in FIG. 7, electricity generated from the generator 2 is supplied to the regenerator 11 and compressor 3. The first and second reversing valves 4 and 13 operate in a heating mode, and the first, second, third, fourth, fifth, sixth, seventh, and eighth 3-way valves 71, 72, 73, 74, 75, 76, 77, and 78 operate in a heating mode. The heat medium circulation pump 61 is driven.

The first and second 3-way valves 71 and 72 open the second heat medium circulation conduit 63 to cause the heat medium emerging from the regenerator 11 to circulate through the second heat medium circulation conduit 63. The fifth and sixth 3-way valves 75 and 76 close the cooling heat exchanger circulation conduit 66. The seventh and eighth 3-way valves 77 and 78 open the bypass conduit 68, thereby causing the refrigerant supplied toward the compressor 3 to be introduced into the suction-side overheating heat exchanger 62 via the bypass conduit 68.

The heat medium pumped by the heat medium circulation pump 61 is heated while passing through the cooling water heat exchanger 22, and is then introduced into the exhaust gas heat exchanger 21. After re-heated in the exhaust gas heat exchanger 21, the heat medium is introduced into the regenerator 11. After transferring the heat to the regenerator 11, the heat medium passes through the suction-side overheating heat exchanger 62 to heat-exchange with the suction-side overheating heat exchanger 62. Thereafter, the heat medium returns to the cooling water heat exchanger 22.

The refrigerant introduced into the suction-side overheating heat exchanger 62 is heated by the heat medium passing through the suction-side overheating heat exchanger 62. The heated refrigerant passes through the first reversing valve 4 and the first indoor heat exchanger 5 after being compressed by the compressor 3. Since the refrigerant is re-heated in the suction-side overheating heat exchanger 62, heat of a higher temperature is released from the refrigerant. Accordingly, the heating performance of the compression type air conditioner 10 is enhanced.

On the other hand, when the compression type air conditioner 10 operates in a heating mode in the OFF state of the absorption type air conditioner 20, as shown in FIG. 8, the electricity generated from the generator 2 is supplied only to the compression type air conditioner 10. In this case, the first, second, fifth, sixth, seventh, and eighth 3-way valves 71, 72, 75, 76, 77, and 78 are controlled to be in a heating mode. On the other hand, the third and fourth 3-way valves 73 and 74 are controlled to be in an OFF mode.

That is, the first and second 3-way valves 71 and 72 open the second heat medium circulation conduit 63 to guide the heat medium into the second heat medium circulation conduit 63. The third and fourth 3-way valves 73 and 74 open the third heat medium circulation conduit 64 to prevent the heat medium from being introduced into the regenerator 11. The fifth and sixth 3-way valves 75 and 76 close the cooling heat exchanger circulation conduit 66. The seventh and eighth 3-way valves 77 and 78 open the bypass conduit 68.

Accordingly, the heat medium heated in the cooling water heat exchanger 22 is introduced into the exhaust gas heat exchanger 21, and is re-heated while passing through the exhaust gas heat exchanger 21. Thereafter, the heat medium passes through the third 3-way valve 73, third heat medium circulation conduit 64, and fourth 3-way valve 74, in the order named, enters the suction-side overheating heat exchanger 62 via the first 3-way valve 71 and second heat medium circulation conduit 63, and then returns to the cooling water heat exchanger 22.

On the other hand, when the absorption type air conditioner 20 operates in a heating mode, and the compression type air conditioner 10 is in an OFF state, as shown in FIG. 9, the electricity generated from the generator 2 is supplied only to the absorption type air conditioner 20.

In this case, the first and second 3-way valves 71 and 72 close the second heat medium circulation conduit 63, and the seventh and eighth 3-way valves 77 and 78 close the bypass conduit 68.

Accordingly, the heat medium heated in the cooling water heat exchanger 22 passes through the exhaust gas heat exchanger 21, regenerator 11, first 3-way valve 71, and second 3-way valve 72, in the order named, and then returns to the cooling water heat exchanger 22.

On the other hand, when both the compression type air conditioner 10 and the absorption type air conditioner 20 operate in a cooling mode, as shown in FIG. 10, the electricity generated from the generator 2 is supplied to both the compression type air conditioner 10 and the absorption type air conditioner 20.

In this case, since the absorption type air conditioner 20 requires a heat source supplied from the regenerator 11 regardless of the operation mode (cooling or heating mode) of the absorption type air conditioner 20, the heat medium, which sequentially passes through the cooling water heat exchanger 22 and exhaust gas heat exchanger 21, is supplied to the regenerator 11 without being introduced into the suction-side overheating heat exchanger 62.

That is, the first and second 3-way valves 71 and 72 close the second heat medium circulation conduit 63, whereas the seventh and eighth 3-way valves 77 and 78 close the bypass conduit 68.

Accordingly, the heat medium heated in the cooling water heat exchanger 22 is introduced into the exhaust gas heat exchanger 21, so that the heat medium is re-heated in the exhaust gas heat exchanger 21. The heated heat medium is supplied to the regenerator 11, and then returns to the cooling water heat exchanger 22 via the first and second 3-way valves 71 and 72.

The regenerator 11 produces refrigerant vapor, using heat transferred from the heat medium. The produced refrigerant vapor passes through the second reversing valve 13, second outdoor heat exchanger 16, second expansion device 15, and second indoor heat exchanger 14, in the order named, thereby cooling indoor air.

On the other hand, when the compression type air conditioner 10 operates in a cooling mode, and the absorption type air conditioner 20 is in an OFF state, as shown in FIG. 11, the electricity generated from the generator 2 is supplied only to the compression type air conditioner 10.

In this case, the heat medium heated by the cooling water heat exchanger 22 and exhaust gas heat exchanger 21 releases heat to the cooling heat exchanger 65.

That is, the third and fourth 3-way valves 73 and 74 open the third heat medium circulation conduit 64, the first and second 3-way valves 71 and 72 open the second heat medium circulation conduit 63, and the fifth and sixth 3-way valves 75 and 76 open the cooling heat exchanger circulation conduit 66.

Accordingly, the heat medium, which sequentially passes through the cooling water heat exchanger 22 and exhaust gas heat exchanger 21, is introduced into the third heat medium circulation conduit 64 via the third 3-way valve 73, is introduced into the second heat medium circulation conduit 63 via the first 3-way valve 71, and is then introduced into the cooling heat exchanger circulation conduit 66 via the fifth 3-way valve 75.

The heat medium introduced into the cooling heat exchanger circulation conduit 66 returns to the cooling water heat exchanger 22 via the sixth 3-way valve 76 after releasing heat to the cooling heat exchanger 65.

The cogeneration system according to any one of the above-described embodiments of the present invention has various effects.

That is, the cogeneration system according to the present invention is configured such that waste heat generated from the drive source such as an engine is used in at least one of the compression type air conditioner and absorption type air conditioner. Accordingly, an increase in cooling/heating capacity is achieved. Since the absorption type air conditioner can use the waste heat during the cooling mode thereof, the enhancement of the efficiency can be achieved by using the waste heat.

In the cogeneration system as illustrated, the electricity generated from the generator may be used in the compression type air conditioner, and the waste heat generated from the drive source may be used in the absorption type air conditioner. Therefore, the system efficiency is enhanced by using waste heat.

Since the temperature of the waste heat recovered by the exhaust gas heat exchanger is higher than the temperature of the waste heat recovered by the cooling water heat exchanger, the cogeneration system according to the present invention may be configured such that the waste heat recovered by the exhaust gas heat exchanger is used in the regenerator of the absorption type air conditioner, which requires a heat source of a higher temperature, and the waste heat recovered by the cooling water heat exchanger is used in the suction-side overheating heat exchanger. In this case, a more efficient system may be implemented by using waste heat.

Also, the cogeneration system as illustrated may be configured such that the heat medium heated in the cooling water heat exchanger is supplied to the regenerator of the absorption type air conditioner after being re-heated in the exhaust gas heat exchanger, and is subsequently used in the suction-side overheating heat exchanger after heat-exchanging with the regenerator. In this case, the heat of a relatively high temperature is supplied to the regenerator because the heat medium is supplied to the regenerator after sequentially passing through the cooling water heat exchanger and exhaust gas heat exchanger. The heat medium, which has heat-exchanged with the regenerator, is used in the suction-side overheating heat exchanger. Accordingly, a more efficient system may be implemented by using waste heat.

Although the preferred embodiments of the invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims. 

1. A cogeneration system comprising: a compression air conditioner including a compressor, a first heat exchanger and a second heat exchanger; an absorption air conditioner including a regenerator, an absorber, a third heat exchanger and a fourth heat exchanger; a generator which generates electricity; a drive source which drives the generator to generate the electricity for operating the compression air conditioner and the absorption air conditioner and generates waste heat when driving the generator; and a waste heat recoverer which recovers the waste heat of the drive source and supplies the recovered waste heat to at least one of the compression air conditioner and the absorption air conditioner.
 2. The cogeneration system according to claim 1, wherein the waste heat recoverer comprises: an exhaust gas heat exchanger which absorbs the waste heat from exhaust gas discharged from the drive source; a cooling water heat exchanger which absorbs the waste heat from cooling water used to cool the drive source; and a heat transfer unit which transfers the waste heat from at least one of the exhaust gas heat exchanger and the cooling water heat exchanger to at least one of the compression air conditioner and the absorption air conditioner.
 3. The cogeneration system according to claim 2, wherein the heat transfer unit comprises: a heat medium circulation conduit which guides a heat medium heated by at least one of the exhaust gas heat exchanger and the cooling water heat exchanger, into the regenerator of the absorption air conditioner, thereby transferring the waste heat to the regenerator; and a heat medium circulation pump which pumps the heat medium for circulation of the heat medium.
 4. The cogeneration system according to claim 3, further comprising: a cooling heat exchanger which cools the heat medium heated by at least one of the exhaust gas heat exchanger and the cooling water heat exchanger, when the absorption air conditioner is in an OFF state; and a cooling heat exchanger circulation conduit connected to the heat medium circulation conduit to guide the heat medium to circulate through the cooling heat exchanger.
 5. The cogeneration system according to claim 4, further comprising: a valve unit which controls the heat medium circulation conduit and the cooling heat exchanger circulation conduit such that the heat medium circulates through the cooling heat exchanger circulation conduit when the absorption air conditioner is in the OFF state, and circulates through the heat medium circulation conduit when the absorption air conditioner is in an ON state.
 6. The cogeneration system according to claim 5, wherein the heat medium circulation conduit guides the heat medium heated by the cooling water heat exchanger, such that the heat medium is re-heated in the exhaust gas heat exchanger, and then returns to the cooling water heat exchanger after transferring heat to the regenerator.
 7. The cogeneration system according to claim 1, further comprising: a suction-side overheating heat exchanger which supplies the waste heat recovered by the waste heat recoverer to the compression air conditioner.
 8. The cogeneration system according to claim 7, wherein the waste heat recoverer comprises: an exhaust gas heat exchanger which absorbs the waste heat from exhaust gas discharged from the drive source; a cooling water heat exchanger which absorbs the waste heat from cooling water used to cool the drive source; and a heat transfer unit which transfers the waste heat from at least one of the exhaust gas heat exchanger and the cooling water heat exchanger to at least one of the compression air conditioner and the absorption air conditioner.
 9. The cogeneration system according to claim 8, wherein the heat transfer unit comprises: a first heat medium circulation conduit which guides a first heat medium heated by one of the exhaust gas heat exchanger and the cooling water heat exchanger, into the regenerator, thereby transferring the waste heat to the regenerator; and a second heat medium circulation conduit which guides a second heat medium heated by the other one of the exhaust gas heat exchanger and the cooling water heat exchanger, into the suction-side overheating heat exchanger, thereby transferring the waste heat to the suction-side overheating heat exchanger.
 10. The cogeneration system according to claim 9, further comprising: a cooling heat exchanger which cools the first heat medium and the second heat medium respectively heated by one of the exhaust gas heat exchanger and the cooling water heat exchanger, when the absorption air conditioner is in an OFF state or when the compression air conditioner operates in a cooling mode; a first cooling heat exchanger circulation conduit connected between the cooling heat exchanger and the first heat medium circulation conduit; and a second cooling heat exchanger circulation conduit connected between the cooling heat exchanger and the second heat medium circulation conduit.
 11. The cogeneration system according to claim 10, further comprising: a first valve unit which guides the second heat medium such that the second heat medium circulates through the second cooling heat exchanger circulation conduit when the compression air conditioner operates in a cooling mode, and circulates through the second heat medium circulation conduit when the compression air conditioner operates in a heating mode.
 12. The cogeneration system according to claim 11, further comprising: a refrigerant circulation conduit which guides a refrigerant into the compressor; a bypass conduit which guides the refrigerant through the suction-side overheating heat exchanger when the compression air conditioner operates in the heating mode; and a second valve unit which guides the refrigerant to pass through a selected one of the refrigerant circulation conduit and the bypass conduit.
 13. The cogeneration system according to claim 8, wherein the heat transfer unit comprises: a first heat medium circulation conduit which guides a heat medium heated by the cooling water heat exchanger, such that the heat medium is re-heated by the exhaust gas heat exchanger, and then returns to the cooling water heat exchanger after transferring heat to the regenerator of the absorption air conditioner; and a second heat medium circulation conduit connected to the first heat medium circulation conduit to guide the heat medium emerging from the regenerator, to guide through the suction-side overheating heat exchanger when the compression air conditioner operates in a heating mode.
 14. The cogeneration system according to claim 13, further comprising: a first valve unit which controls the first heat medium circulation conduit and the second heat medium circulation conduit such that the heat medium circulates through the first heat medium circulation conduit when the absorption air conditioner is in an ON state and the compression air conditioner operates in a cooling mode, and such that the heat medium emerging from the regenerator circulates through the suction-side overheating heat exchanger via the second heat medium circulation conduit when the compression air conditioner operates in the heating mode.
 15. The cogeneration system according to claim 14, further comprising: a third heat medium circulation conduit connected to the first heat medium circulation conduit to guide the heat medium such that the heat medium bypasses the regenerator when the absorption air conditioner is in an OFF state.
 16. The cogeneration system according to claim 15, further comprising: a second valve unit which controls the first heat medium circulation conduit and the third heat medium circulation conduit such that the heat medium passes through the third heat medium circulation conduit when the absorption air conditioner is in the OFF state, and passes through the first heat medium circulation conduit when the absorption air conditioner is in the ON state.
 17. The cogeneration system according to claim 16, further comprising: a cooling heat exchanger which cools the heat medium when the compression air conditioner operates in the cooling mode; and a cooling heat exchanger circulation conduit connected to the second heat medium circulation conduit to guide the heat medium to circulates through the cooling heat exchanger.
 18. The cogeneration system according to claim 17, further comprising: a third valve unit which controls the second heat medium circulation conduit and the cooling heat exchanger circulation conduit such that the heat medium circulates through the cooling heat exchanger circulation conduit when the compression air conditioner operates in the cooling mode and the absorption air conditioner is in the OFF state of, and circulates through the second heat medium circulation conduit when the compression air conditioner operates in the heating mode.
 19. The cogeneration system according to claim 18, further comprising: a refrigerant circulation conduit which guides a refrigerant into the compressor; a bypass conduit which guides the refrigerant through the suction-side overheating heat exchanger when the compression air conditioner operates in the heating mode; and a fourth valve unit which guides the refrigerant, which is sucked toward the compressor, to pass through a selected one of the refrigerant circulation conduit and the bypass conduit.
 20. The cogeneration system according to claim 1, further comprising: a cooling heat exchanger which cools a heat medium emerging from the waste heat recoverer.
 21. The cogeneration system according to claim 1, wherein the compression air conditioner further includes a reversing valve and an expansion device.
 22. The cogeneration system according to claim 1, wherein the absorption air conditioner further includes a reversing valve and an expansion device.
 23. A method of utilizing waste heat of a drive source, comprising the steps of: generating the waste heat from the drive source when the drive source drives to generate electricity; and supplying the waste heat to at least one of a compression air conditioner and a absorption air conditioner.
 24. The method of claim 23, wherein the step of supplying the waste heat includes: absorbing the waste heat from exhaust gas discharged from the drive source; absorbing the waste heat from cooling water used to cool the drive source; and transferring the waste heat absorbed from the exhaust gas and the waste heat absorbed from the cooling water to at least one of the compression air conditioner and the absorption air conditioner.
 25. The method of claim 24, wherein the step of transferring the waste heat includes transferring the waste heat to a regenerator of the absorption air conditioner by providing a heat medium circulation conduit which guides a heat medium heated by at least one of the exhaust gas and the cooling water into the regenerator of the absorption air conditioner when the absorption air conditioner is in an ON state.
 26. The method of claim 25, further comprising the step of cooling the heat medium when the absorption air conditioner is in an OFF state by providing a cooling heat exchanger circulation conduit connected to the heat medium circulation conduit to guide the heat medium to circulate through a cooling heat exchanger.
 27. The method of claim 24, wherein the step of transferring the waste heat includes: supplying the waste heat absorbed from the exhaust gas to a regenerator of the absorption air conditioner via a first heat medium; and supplying the waste heat absorbed from cooling water to the compression air conditioner via a second heat medium when the compression air conditioner operates in a heating mode.
 28. The method of claim 27, further comprising the step of cooling the first heat medium when the absorption air conditioner is in an OFF state by providing a first cooling heat exchanger circulation conduit to guide the heat medium to circulate through a cooling heat exchanger.
 29. The method of claim 27, further comprising the step of cooling the second heat medium when the compression air conditioner operates in a cooling mode by providing a second cooling heat exchanger circulation conduit to guide the heat medium to circulate through a cooling heat exchanger.
 30. The method of claim 29, further comprise the steps of: circulating the second heat medium through the second cooling heat exchanger circulation conduit to cooling heat exchanger when the compression air conditioner operates in the cooling mode; and circulating the second heat medium through a second heat medium circulation conduit when the compression air conditioner operates in the heating mode.
 31. The method of claim 30, further comprise the steps of: guiding a refrigerant for the compressor to receive the waste heat absorbed from the cooling water when the compression air conditioner operates in the heating mode; and guiding the refrigerant for the compressor to not receive the waste heat absorbed from the cooling water when the compression air conditioner operates in the cooling mode.
 32. The method of claim 24, wherein the step of transferring the waste heat includes transferring the waste heat to a regenerator of the absorption air conditioner by providing a heat medium circulation conduit which guides a heat medium heated by the exhaust gas and the cooling water into the regenerator of the absorption air conditioner.
 33. The method of claim 32, wherein the step of transferring the waste heat includes: guiding the heat medium heated by the cooling water via a first heat medium circulation conduit to be reheated by the exhaust gas and then into the regenerator of the absorption air conditioner; and guide the heat medium emerging from the regenerator via a second heat medium circulation conduit to transfer the waste heat to the compression air conditioner when the compression air conditioner operates in a heating mode.
 34. The method of claim 33, wherein the step of guiding the heat medium heated by the cooling water via the first heat medium circulation conduit includes circulating the heat medium through the first heat medium circulation conduit when the absorption air conditioner is in an ON state and the compression air conditioner operates in a cooling mode; and wherein the step of guiding the heat medium emerging from the regenerator via the second heat medium circulation conduit includes circulating the heat medium through the second heat medium circulation conduit when the compression air conditioner operates in the heating mode.
 35. The method of claim 34, further comprising guiding the heat medium via a third heat medium circulation conduit to bypass the regenerator when the absorption air conditioner is in an OFF state
 36. The method of claim 35, further comprising the step of cooling the heat medium when the absorption air conditioner is in the OFF state by providing a cooling heat exchanger circulation conduit connected to the second heat medium circulation conduit to guide the heat medium to circulate through a cooling heat exchanger.
 37. The method of claim 36, further comprising the steps of: circulating the heat medium through the cooling heat exchanger circulation conduit when the absorption air conditioner is in the OFF state and the compression air conditioner operates in the cooling mode; and circulating the heat medium through the second heat medium circulation conduit when the compression air conditioner operates in the heating mode.
 38. The method of claim 37, further comprise the steps of: guiding a refrigerant for the compressor to receive the waste heat when the compression air conditioner operates in the heating mode; and guiding the refrigerant for the compressor to not receive the waste heat when the compression air conditioner operates in a cooling mode. 